Facebook’s Menlo Park headquarters were locked down for over an hour on Tuesday night after police received a bomb threat against the social media giant. The threat was ultimately determined to be “unsubstantiated and not credible.”

The threat was called in to the San Francisco Police Department, which then notified Menlo Park police at 7:10 p.m.

“Based on this possible threat, the Menlo Park Police Department followed standard operating procedures and sent officers to the Facebook campus and advised Facebook personnel,” Menlo Park police Cmdr. Dave Bertini said in a statement. “Facebook personnel held employees at the site until officers were on scene. The threat was determined to be unsubstantiated and not credible and officers began to clear the scene at about 8:30 p.m. Facebook employees then began to leave the campus normally.”

“#Facebook is on lockdown right now. Cops are everywhere! Two big busses on the outside with #cops behind them anybody know why?”an Instagram user wrote.

Facebook soon will have its own full-time sworn police officer at a substation near its campus, funded by the company at a cost of $200,000 a year for three years.